VO2 max: are you training the wrong limiter? | Evan Peikon

Are you a hybrid athlete who wants to learn more about how to combine your strength and endurance training? Well, I've written a new book, The Science of Hybrid Training. In this book, I provide insight into the misconceptions surrounding strength and endurance training by distilling the past 50 years of research and drawing on the conversations I had with great scientists, coaches and athletes on the progress theory podcast. This book is a central reading for hybrid athletes and coaches who are looking to understand the key training variables and their effect on the simultaneous development of strength and endurance performance. Get your copy now available to buy from Amazon. Now let's get into the show. Hello and welcome to the progress theory where we discuss scientific principles for optimizing human performance. I am Dr. Phil Price and we are back back in this new studio and we've got a great episode for you. We are drawn by physiologists and CrossFit Coach Evan Picon. Now we've had Evan on the podcast before and those episodes are really, really popular so make sure you go back and check those out. However, he has recently got in contact with me saying that he's just updated his book, Paradime Shift and he's going to come on the podcast today and discuss energy systems and how we can utilize science to improve our training for hybrid athletes. If you enjoy science and how to apply it, this is the episode for you. As always, check out one of our content on YouTube and Instagram and we've got loads of great episodes coming out so make sure you stay tuned. Anyway, straight to this episode, here is Evan Picon. Evan, it's so good to have you back on the progress theory. How are you? I'm doing well. How are you? Not too bad. As you can tell, there's been quite a few changes around here, especially with the backdrop. Newhouse, two kids. There's been a whirlwind, but absolutely right. How about yourself? Yeah, everything's gone well here as well. Yeah, I've got a new backdrop too. No kids on my end, but yeah, it's definitely been a while since we've got up. Yeah, well, it's been the big news since we last spoke. Yes, so since we last spoke, a few things have gone on. One, I was able to exit from Nox, so that was kind of a big shift, and then I've been working on my PhD for a while now, so that's been kind of the big lifestyle change. I'm also working with the handful of different sports tech companies now, so kind of across the board, a little bit of a difference that up. What made you leave Nox? Was it deliberately to branch out a little bit more with several sort of sporting tech companies? We had some opportunities to kind of pivot the company away from a direct consumer company, to some different business opportunities, more and like the enterprise and technology development side. So that was really a big thing there, and then on my end, just working on my PhD and wanting to be able to work with different technologies, it's kind of a nice fit to be able to combine those two things. PhD gives a little bit of flexibility, consulting and advisory work, also gives some flexibility, and I'm personally someone that likes to be involved in a lot of different types of projects, so it's nice for me to be able to kind of bounce around. You struggle with just focusing on the one, you're like, well, I have interest here, interest here, interest here. You just want to touch base in all of them. Yeah, that's definitely it. Yeah, I have like multiple different kind of like avenues of research and work that I'm interested in, and yeah, it's hard for me to just say, I want to only be doing work in the human performance space, or I only want to be working on oncology. I want to kind of do everything at all times. Yeah, I can feel that. What's the PhD on oncology, or? Yeah, so kind of going on the theme of doing a lot of different things. My PhD work is split in half, half of it is precision oncology. On half is biodefense, so the actual PhD itself is in computational biology, so I spend basically half my week essentially what we're trying to do is identify like new molecular subtypes of breast cancer, and then identify like rational personalized therapeutic targets, so being able to say like, okay, all these people have breast cancer, what's differentiating the metamolecular level, and then knowing that what would be like a highly precise drug target for a specific patient, and then on the biodefense side, primarily working on systems to predict like clinical symptoms from novel pathogen exposures, so if you imagine like a new pandemic, you don't know what the symptoms of it are going to be, and you don't want to wait for a hundred thousand people to get infected to be able to say like, this is the symptom, if you notice x, y, z, stay at home, so the idea there is, can we predict all the range of clinical symptoms that you would see from a novel pathogen before anyone gets infected, and then on the tail end of that, can we develop like algorithms that you could deploy on common wearable devices that would be able to flag these things before people are symptomatic, and then obviously they could like shelter in place and not get other people sick. Did you find that moving into that space was relatively seamless because of your work on human performance anyway from a sporting context, and your work with wearable tech? Yeah, a little bit of both, so oddly a lot of things, you know, anyone working in the human performance space, we would just kind of take for granted, or kind of paradigms that are interesting to bring into something like precision oncology, so that was helpful, like for example, with training, you're like, you know, time of day is going to impact training, you know, that like all these different confounding factors, nutrition, stress recovery, we're going to impact training adaptation. That's something that you know, we talk to SMC coaches and like, yeah, obviously the same thing also applies with giving a patient drugs, you're like time of day is going to influence how they respond to all these other factors, so there were definitely things that smooth the transition allowed me to bring some ideas in. The harder things were technical, so thankfully it knocks a lot of my job, but it was like algorithm development and taught myself code rendering that, so I work like an Encyclical Lab, so it's all computational, so there were some specific things that were a little bit more challenging to pick up. And what's the end goal? Once the PhD's done, obviously, usually you do a PhD to learn research skills into the next stage. What is the next stage? Would you think? That's a great question, yeah, so I'm not, you know, I have no intent to stay in academia, so I'm not going to go down the postdoc on route, associate professor kind of thing. Ideally, I'd like to be able to work in, essentially, at all times, do something in precision oncology, something in bio-defense and something in human performance, whether that's, you know, starting my own outfit in one of those spaces again or working with, you know, essentially a company or an organization in each of those, maybe it might even be like working with an academic lab part-time, working with startup companies, the rest of the time, so I don't have the exact plan, but some kind of ideas scooped out. It seems more and more now. I don't know if this is just a UK thing or you've noticed it as well, especially with the development of AI. More and more people have kind of done the PhD, but then they've gone and set up their own startup as an opportunity to do that research and get really stuck into a research project and also be creating of something, rather than staying in academia to be able to do that, because I guess, you know, your time's taken up with a lot of teaching and marking and all that type of thing. You don't get that opportunity, but if you were, if you had your own startup, then you could focus on the bits that you really want to. Yeah, I think that's definitely part of it, and that's something where a lot of particularly biotech founders, a lot of the more postdocs, and then they sentry spun out the technologies from the labs that they were working in to be able to do it in like a company fashion. It definitely does have some advantages. Also has some downsides as well, but yeah, I think it does give you a nice opportunity to accelerate research and, you know, kind of cut a lot of the red tape that you would have to deal with in academia, where you do have other responsibilities that aren't necessarily about pushing the project forward. What made you redirect your stuff to the human performance work? Most notably, redoing, or let's say redoing, updating paradigm shift. Yeah, for sure. So about two years ago, even while we were building NOx and we were kind of taking that towards some like medical routes and I was working on the PhD, I honestly thought that I wouldn't come back to the human performance space. I was getting really into precision oncology and biodefense work and felt really passionate about that. And it was like, okay, I think this is what I'm going to do now, kind of spend my time on both of these domains. And then inevitably, you know, like an old pro sport contact will be like, hey, I have this project that sounds interesting. Could you help? And I'm like, oh, that sound really interesting. And then I'll go watch a professional cycling race. And I'm like, oh, I would really like to work with one of these teams one day. And you just kind of get sucked back in. So it was really driven by that kind of, I thought I had made the conscious decision to step away from this space. And then, you know, it kind of pulled me back in. And I realized how much I actually did miss working with athletes and teams. And then after doing that, a lot of the things that I did work on in recent years with teams, I wasn't really allowed to talk about publicly just because of the nature of that work was doing a lot of like R&D for teams or working with their data for different applications. So you can't just go and tell the world about that. And I was like, well, I have learned a lot during that time. And obviously without sharing any specific like teams or athletes data, like there were some principles in general training ideas that I wanted to try and get out there. So it's like, I'm going to rewrite paradigm shifts which I had originally written in 2019 or 2020, I believe. That's a good one. I want to redo this and kind of integrate everything that I've owned over the years that I haven't been able to speak to. So what changed the most? Because in the original paradigm shift, you were quite critical with the original energy systems model, particularly around this idea that you focus on one energy system, then it moves to the next as that sporting activity prolonged. And you know, it's playing really well the issues with that. So is that still the key core of where paradigm shift comes from? Because I know you talk about your work with training think tank, and how you developed your model based on the issues that you were seeing. Is that still like a core component? And then it's more the practical side, which is the new stuff within the book. Yes, so that was definitely the core component, really like seeing that schism between how energy systems are traditionally taught, and then what you could measure with some of these modern technologies. That was kind of the seed that you know, really planted everything else that was to come. The biggest things that have changed since the original version is one more of a focus on cardiovascular control mechanisms. So really thinking about, you know, quite honestly, I don't really think about energy systems or so what's happening at like a molecular level during exercise. I think more about what are these control systems in the body? So how is the muscular system interacting with the cardiovascular system? How is blood pressure regulation impacting how we could get blood to the muscles? How's the sympathetic nervous system constraining blood flow? And I think once you could get that perspective and understand how all these systems are working together, a lot of your observations about training really start to reflect together. So for example, you might have a athlete with a cardiovascular limitation, and they might be training to improve their local muscle endurance, and they're not really getting a lot of bang for your buck. And if you start to think about why that's the case, you realize you're like, oh, one, they're not limited by what's happening in the muscle. They're limited by their ability to get blood there. Well, why don't they just do more zone two training? For example, you're like, well, why doesn't that work? Oh, it's because they can't regulate their own blood pressure. Why can't they regulate your own blood pressure? And you eventually arrive at the conclusion that's, you know, generally a really straightforward observation. So that's definitely one of the big shifts. The other one is quite frankly, technology has just changed a lot over the past five or six years. There's a lot of sense in technologies that were just prohibitively expensive five or six years ago. That if I were working with sports teams or military, we would get access to these things. But, you know, they're $15,000, $20,000, and now they're the same sense in technologies. You know, the average person could pick them up for $1 or $200. So that was the other biggest shift. Wanting to incorporate more of that into the book because in the original copy, I didn't want to talk about those things because some like, the average person's never gonna touch them. It's not useful. So I wanted to bring more of that experience in and then just speak to more of like this system's view of how the body works, which was more informed by even, like my cancer research, for example. After rereading volume two, I definitely felt the message of how athletes could improve performance, but they wouldn't necessarily improve the physiological mechanisms behind it. Almost to the point where the improvements in performance would mask any improvement that they actually made and could lead to poorer decisions being made further down the line. So that was really cool to see and you gave some really good examples how to use, but nox in your case, but near as in general. And yeah, it's crazy how I thought you'd talk about 2019 when you originally made it with 2006 now. It was only seven years and technology has just really, really developed exponentially in that time. All of a sudden we're gonna see loads of change in how people track and understands how their athletes are improving and therefore write better programs. But do you think there's a little bit of a lag? Because technology has really improved. It's now accessible, but we may not have the understanding to be able to maximize that as much as possible hence why a book like Powered Unship can really help with that. - Yeah, I think that's a big part. So yeah, if we go back six or seven years, data collection hadn't really taken off. Now we're at the point where data one from being inaccessible to highly accessible. And you know, you work with a lot of athletes and they're collecting multiple data streams. They, you know, if they're their endurance athlete, maybe they use a woofer or a slip, all the data that you're gonna get from that, they probably have a power meter. They're pulling in GPS data. But right now we're still at the point where when you look at all of the data that a given individual's collecting, the sum is equal to the parts. IE, it's all just stacked together. Where we need to go is that the sum of all the data streams is greater than the parts. So this is where you start to get into more of like ideas around emergence. If we combine this data in the right way, we could come out with something on the tail end that is more than just saying we collected HRV and sleep and heart rate and blood glucose. We could say, what is causing what? What is mediating these effects? And that's where I think the field is eventually going to go. It's actually already quite possible. It's just that most people haven't moved to that place. But there's absolutely sports teams and organizations that are already doing this where we could say, okay, we know the outcome that an individual cares about. We have all of this data and we could start to say, okay, you care about improving your maximal sprint speed, but we could say 20% of that is mediated by lifestyle factors and those specific lifestyle factors for you are XYZ. On the training side, that is mediated by these factors and eventually what you could get on the tail end of that is like, what are the exact levers that you need to pull to drive this change? But as an industry, I don't think we've really quite gotten there yet. Just so we can discuss that in a bit more detail, especially like, okay, this is the situation you try this. Is it right if we take it back and discuss, I guess archetypes, maybe it's the best way I've described it or not, of limiters. So utilization, limitation, spiritually limitation, those types of ones. Would you be able to just give a synopsis of each one and maybe, you know, physiologically, what makes them limited in that area? - Yeah, absolutely, so kind of big picture of the limiters. I like to use VO2 maxes kind of a gross proxy here to anchor it. So first, if we think about what VO2 maxes, it is the maximum integrated capacity of your pulmonary or your respiratory system to uptake oxygen, get it into your body, your cardiovascular system to supply that oxygen to tissues and then your muscle tissues ability to use oxygen. Traditionally, if you read some of the old like AV Hill research in the 1920s, it's theorized that VO2 is principally limited by your stroke volume and that's kind of a thing that's been repeated for decades after, which is kind of funny because in that original paper, they have calculations how they arrived to that conclusion and they weren't actually able to measure most of those things because the technology didn't exist for another 50 or 60 years. So essentially like they took a flyer, made the synopsis and it's been repeated for decades after. So when we're speaking about limiters, I'm primarily speaking about what of these systems is limiting your maximal oxygen consumption. Is it your respiratory system? Is it your cardiovascular system? Is it your muscular system? Then within each of those, there are actually some like sublimitations you could call them. So if we were to speak to the muscular system first, this one is the most straightforward. Do you have sufficient mitochondrial and capillary density to utilize oxygen in your muscles? Yes or no question. So the way that you would typically diagnose this is if you put a nearest device on someone and you're looking at their tissue oxygenation during exercise, we'll say okay, hop on a bike and just go all out for 30 seconds. This is kind of like the most crude assessments. And what we'll see is one of two things. We'll either see that oxygen in the muscle bottoms out really fast and once they deplete their oxygen supplies, the athletes pretty much toasted or we'll see that oxygen saturation in the muscle just doesn't change that much. For that latter person, that's their rate limiting factor. You could improve their cardiovascular or their respiratory system's capacity over and over and over again and they're not gonna get any better because their problem isn't getting oxygenated blood to their working muscles. The blood's already getting there. It's the fact that they're not utilizing the oxygen. Then on the opposite ends, you have what we'd call delivery limitation which is more of like a crude name for cardiovascular limitation. This person's problem is that they can't actually supply blood to the working muscles. Traditionally, this would be thought of as like a cardiac output or stroke volume issue. The way that I think about this is really more of a blood pressure regulation issue though. And the example that I give is if you were to take like a faucet in your house to turn on the tap. If you were to do that, you know, you open it, your water pressure is fine. Imagine if you expand it all of the pipes in your house's diameter by 50% and then you open up the tap and you're like water is gonna trickle out 'cause your water pressure is low. In your body, that situation is not going to be allowed because your sympathetic nerve system prevents it. So when you're exercising and you're utilizing oxygen in your muscles which these delivery and limited athletes are good at doing, they typically have very good mitochondrial and capillary density, there's gonna be a compensatory increase blood flow to that muscle. But the only way to increase blood flow is to expand the diameter of the pipes. Now, what happens if your cardiac output isn't high enough that when you expand the volume of those pipes, you could maintain blood pressure. Your brain's not going to let you do that. You'll quite literally black out instantaneously. So the sympathetic nerve system is going to restrain blood flows. And we think of those delivering limited athletes. What we're really saying is like, why can't they regulate their own blood flow? And that's going to be their primary limitation. Then on the opposite end of the spectrum, we have respiratory limited athletes, which is kind of the phenotype that you would see in the lead endurance athlete. Now, there's a lot of different types of respiratory limitations. But the kind of like most potent one that you would see if you were to work with a tour de France calber cyclist is that they have what's called the pulmonary diffusion limitation, which is that their cardiac output is so good that they accelerate their red blood cells through the pulmonary capillaries and their lungs. And they don't have time to pick up oxygen. So these individuals end up in a scenario where when red blood cells leave their heart, they're ready partially deoxygenated. And they're getting that blood to the tissues just fine, but it doesn't have the substrate that they need to perform. So what you end up with is not only these three types of limitations that would impact some ones, you know, VO2 max, for example, but things that end up having downstream consequences for effectively any type of training they do, whether it's energy system training or strength training. And these things manifest differently in different sports, but essentially they create these like fingerprints or patterns that if you were to go into CrossFit, you're like, oh, there's a certain like phenotype that a delivery limited athlete ends up with. And when you know it, you could easily spot it. It's going to be different than a delivery limited athlete and professional cycling. But each of those has these kind of like residues associated with them. And it makes it essentially easier on the back end to flag what that is and that it gives you a centrally targeted training protocols to fix that limiter. Do you often see these limiters more based on level of the athlete or within sport? So you gave the respiratory limited example as an elite cyclist, say, someone that's doing the Tour de France. Our respiratory limited athletes tend to be more elite, and it's kind of like that last component which is holding them back versus delivery and utilization limited athletes can be across the board in terms of level or tend to be lower level or subly athletes. Yeah, so there's a little bit of a kind of selection bias here. So if we were to take like professional cycling, for example, this kind of change is per sport. So if you were to say, well, why does, you know, almost everyone at the elite level and professional cycling have a respiratory limitation? That's partly due to the fact that one, if you did have like a cardiovascular limitation, you would get selected out earlier in the sport. So you're ready creating like a selective pressure, but the second is the respiratory system is unique in that it's really the one organ system that doesn't adapt to exercise in a meaningful way. So your heart adapts to exercise, your muscles obviously adapt to exercise. That's something you could visibly see. In fact, that we no matter how much training you do, your lungs aren't getting any bigger in maximal effort exercise could actually damage the airways to some degree when you have these high flow volumes going through the trachea. So you end up with athletes that have developed everything else to such a high degree that they're really left with having one thing that can be limiting their performance. In other sports, it's a little bit more mixed. So CrossFit is a sport where you do have like more of a heterogeneity at the elite level. CrossFit is shifted more towards selecting respiratory limited athletes in more recent years. Closer to around 2012 to 2015, the game's actually selected more for like a delivery limited athlete phenotype. It's kind of shifted away from that. So that's one that's hard just because you never really know what the sport's going to do. And then something like Hierox would be more of an extreme example of CrossFit where that has more selective pressure for essentially the top athletes being more respiratory limited, potentially even a little bit more utilization limited in that sport. Is that because a lot of high-ups athletes tend to come from like a very good running background. So they've probably gone through that selection already. And they've been weeded out as some of the best already before they've got to high-ups. And we might see a change in, well, will we say a change in that? In a few years, come on just thinking because high-ups is quite a new sport. Whereas compared to your CrossFit example, back in 2012, 2014, it was still a very much a new sport. And I remember in the last episode you talked about how a lot of the athletes were pretty jacked. And that isn't always the best anatomical makeup for, I guess, the ability for muscles to provide tension and relax to help with the return of the oceanated by that type of thing. So yeah, it's really just largely the sport demands a hierarchy. So if you were to take like CrossFit and you wanted someone to compete at the games, you don't have this like true endurance athlete phenotype because you do still need to be reasonably strong to compete at the CrossFit games. Often times the people that are at the top level might not actually be the strongest games competitors, but they still have released respectable strength numbers. If you remove that selective filter and you're saying we don't need you to be that strong anymore, you essentially allow athletes who have more of this respiratory limited phenotype to kind of like rise to the top and the people with more of this delivery limited athlete phenotype that tend to have an easier time gaining muscle increase in their strength, they no longer have a competitive advantage and they end up actually getting pushed down to the bottom. Because CrossFit or every CrossFit games will have different programming and the type of programming might shift with the culture. So it could be really heavily weightlifting dominated for several years before moving to more endurance dominated. Do you feel that could change regularly as the sport continues to develop because obviously high rocks and you know the actual sport itself doesn't actually change. So you don't go through that whereas CrossFit still has that ability to change where all of a sudden someone has a certain genetic profile which would give them a certain advantage because of the type of programming that CrossFit is actually programming at that time. Yeah, no, I mean CrossFit definitely has a greater capacity to change, but I think if you were to do like a sensitivity analysis and take like multiple games stacked to step like stacked back to back, you do see certain athletes kind of excel in across all the different permutations of the games. Despite them kind of change in their focus a little bit, it is still fairly similar year to year, but I do think now that high rocks is getting more popular. I think even from like a business incentive standpoint that might force CrossFit to differentiate in the opposite direction and I suspect that we might see the games getting heavier, a little bit more power based, even partly to create luck and on the athlete standpoint because for CrossFit it's not great if your top competitors are also competing in another sport where they have the ability to make their income there. So I suspect across it will probably try and differentiate where they have their own athletes that they could kind of lock into that sport. Taking it back to the limiters. If we just focus on delivery limitation and utilization limitation first because you provided that really nice near example to explain how that might look, what would the training look like and how would it differ between the two archetypes? Yeah. So I'll start with an easy example just so we could make it really clear and then we could get into more nuanced examples. So what I'm going to start with is just a 500 meter row interval and how we might structure an interval to try and stimulate each of these different limiters and then we could get into what like really good training for each of those it'll look like. So the core idea here is how we structure intensity across a given workabout shifts what physiologic system where prioritize them more or less. So imagine for easy math we have someone with an eight minute to okay. Ideally we would be you know picking a much more competitive pace because really untrained people don't have discrete physiological limiters but for easy math let's pretend that a two in eight minute two case really competitive and that allows me to not have to think too much. Right. So we have a 500 meter row interval at a two minute per 500 pace. So that's just 500 meter row at two k pace. That's one way to structure an interval fixed pace across the entire thing. If you were to get power out with your speed it's just going to be a flat line the entire time. Okay. Now let's try a different way. We're going to go 100 meters at two 10 per 500 meter two oh five two minute one 55 150. Okay so what's happening there? If you look at the power output curve it's increasing linearly across the interval. Average pace is still two minutes per 500 meter. A third way to do it would be what you would think of is really bad pacing but there would be a reason for it which is we're going to go out really hot on this 500 meter. You might even come out at a 135 or 140 which would be pretty hard for someone if that was actually the two k pace and you're going to slow down over the course of the interval in a manner that still averages out to two minute per 500. So on paper we take each of those and let's say the person does eight or 10 intervals and we say okay they did 2000 meters or 4,000. However many intervals at a two minute per 500 meter pace average do those [BLANK_AUDIO] people get the same physiologic adaptation. The answer there's going to be no. So in that case, where we're gradually increasing speed across the interval, what's going to happen is if you're going to look at their tissue oxygenation, you see that they progressively deoxygenate the muscle up this kind of like nice smooth pace. Now, if you're working with an athlete with a delivery limitation, that's going to be a really nice training stimulus because one of the problems for these people is that they can't overcome what's called cardiac lag. So when you start from cold and you start exercising, your cardiac output doesn't just immediately meet the demand, it takes a little while to match for delivery limited athletes because their issue is their cardiovascular systems output. If they train with fixed-paced intervals or even if they come out hot, which would be even worse for them, they're very quickly going to deoxygenate their muscles and their hearts not going to be able to catch up. So they're essentially always going to be in a scenario where they're not matching supply to demands. This is why if we think about cross-fed athletes, someone who tends to gain muscle really easily, very strong cross-fed athlete, this is why these individuals, if they go out hot on workouts, they never recover from that. The whole thing ends up being kind of a shit show on the tail end. The reason why we want to structure it that way, though, physiologically, is so these people have the blood pressure regulation issues, remember. When they're utilizing oxygen in the muscles, they want to vasodilate and get more blood there, but if their heart can't meet that demand and actually increase their cardiac output enough at a fast enough rate to stabilize their blood pressure, they're going to get sympathetic nervous system vasoconstriction. So essentially what you're doing is slowly speeding them up so you could deal with that supply and demand scenario. Now in that case where we go out really hot and then slow down, that's a really great protocol for respiratory limit of athlete. The reason why is for someone with a respiratory invitation, the best way to train is to accumulate a lot of volume close to their VO2 peak. Now the problem is with traditional interval training structures, if your judges do fixed pace, anyone who's done 500 meter repeats at 2k pace knows, it's like the last 30 seconds are typically kind of challenging. The first 90 seconds, you're not really doing that much. So on a per interval basis, ordinary interval training just doesn't stimulate a respiratory limit of athlete that much. And if you wanted to accumulate a lot of volume, that's actually a VO2 peak, you just need to do crazy amounts of set volume, which means a lot of wear and tear on your joints, a lot of training that's not being dedicated to other things. Now if you flip that interval structure and you come out fast, what you do is you get close to VO2 peak very quickly. The problem is you can't sustain that really high effort for a very long time. So what you do is you gradually slow down the speed to stay at a high percentage of VO2 peak across the entire interval and you kind of make the whole thing somewhat terrible, but it allows you to extend out the pace. So that's a way that you're essentially manipulating intro interval pace in, device different limiters that essentially all like high me specific limiter based training protocols or essentially permutations of those ideas of like how do you make that more specific to the sport demands, the athlete, the durations, but that's kind of the core idea. So that's really good examples of the manipulation of interval training essentially. Does that then become the core focus of training overall? As in usually with training, you'd have key hot sessions that will derive a lot of stimulus because there's a high fatigue and component to it. How much emphasis should you place on that? Because obviously with a lot of sports there's a lot of different components to it, maybe skill, maybe other things that they've got to work on. So does this end up making a small component of the overall training or should it be that this is a limitation? This should be the priority over the next however many weeks and then we can reassess as we go along. Yes, the way that I think about it is if we want to try and improve that person's conditioning, so to speak, we need to attack the limiter, but it's obviously not the only thing we need to do. Really the important part of the limiter though is it creates these clear signatures across all different types of training. So this is where what knowing someone's limiter has a lot of benefit beyond just improving their endurance training. For example, it also would apply to their resistance training, their sports specific training, so kind of using some of these other examples. If you have a athlete with a delivery in the mutation, well, knowing that they have problems with blood pressure regulation, if they're doing like heavy resistance training, you're like, well, this is going to have some knock-on effects. For one, it's going to influence their rest periods. They're going to need longer rest periods on average. Typically, they're going to have worse volume tolerance than someone that has a utilization or respiratory limitation. You're also going to want to think about how you pair exercises within resistance training because this person has a problem with regulate in their blood pressure. They're going to have issues with two things. One is back-to-back compound exercises where movements share the same vascular beds. The other is going to be alternating compound movements where they need a different blood flow from their upper to lower body. You're essentially going to be imposing a cardiovascular constraint during their resistance training, which probably isn't the limiter that you want to go after there. On the respiratory limit at the athlete's side, these individuals also struggle out with their diaphragm fatiguing. That's something that you want to address some there, energy system training, but that ends up having an implication in resistance training. For one, movements where you need to brace under pressure for long periods of time, they're going to end up fatiguing their diaphragm heavily so that could become a rate limiting factor on their ability to like height rep squats, for example, instead of the things that you want to be limiting. The other is that you need to be careful with these people's exercise selection because if you're training their respiratory system in high intensity interval training and you're fatiguing their diaphragm, it's a major spinal stabilizer, so you also need to be careful with how you phase like heavy lifting, particularly things that are axioloded with their energy system training to not open up risk of lower back injuries. Then in utilization, I'm at an athlete's side. This is the one that becomes a little bit trickiest because by virtue of these people being limited by their ability to utilize oxygen in the muscle, they're going to be pretty like response refractory with resistance training. These are the kind of like prototypical hardgainers, so if you know that they have a utilization limitation, that's obviously going to inform how you load them in resistance training, then these same things end up manifesting in sport specific work. So a frequent example that I see, I work with a lot of fighters often, so like fighting coaches, kind of from US and internationally, I'll consult with them. One of the things that you see is there's a certain phenotype of fighter that's delivery limited and they tend to feel like they have a muscular endurance limitation when they're fighting, particularly when they're grappling. So in training, they'll do a lot of like local muscular endurance work, and they'll just find that they're not getting any better in the fighting. And typically when I go into these groups and I'm like, hey, you have delivery limitation, you're continuing to improve this person's ability to utilize oxygen in the muscle. Like there's not oxygen for them to utilize. So you could kind of like shift the script and say, well, this is how you should be doing sport specific work and people make rapid improvements. So these things do kind of like cross a lot of different domains. Could you give a bit more of an example of how that went to the point where they were doing in muscular endurance training, what did that look like? And then like you hold on, you know, your muscles don't have the oxygen to use. There's a delivery limitation. So what did then the training look like after, if you know what I mean? Yeah, for sure. So a lot of times in these instances, and this is true with CrossFit as well, people that often think they need to improve their muscular endurance. It's all the things that you'd expect really high rep movements, kind of like agonist, supersets, paired back-to-back, sometimes it's a more sport specific version of that. But this is where if you were to put like near sensors on these individuals, which isn't necessarily something that people need to do, what you tend to find when they do these protocols. So you're like, your tissues are depleted of oxygen right now. You're training to improve mitochondrial density when the substrates isn't there. So oftentimes, muscular endurance for these people ends up looking more like a conditioning, which isn't what they think they need to be doing. There are ways that we could kind of blend that in the more sport specific fashion. So something that we might do with the fighter or CrossFit athlete and the specific movements that they would use in this obviously have to change by their sport is you would want to do say, you were from a two to five kind of gradual ramping interval, maybe on an echo bike, which is a nice kind of modality for these individuals since it is going to move a lot of muscle mass. And then you would have them alternate between lower and upper body movements. Typically, when we start a protocol like this, we choose something that you could do for say 15 to 20 reps, relatively easy. So you might do 15 to 20 air squats continuously and then something upper body that's 15 to 20 reps that you could do continuously. You're essentially what we're trying to do is train their ability to divert blood flow from lower to upper body. And you would do say like lower, upper, lower, upper. And then the next interval, you do the whole thing again, the air bike ramping into lower, upper, lower, upper. And over time, what we want to do is progressively increase the amount of tension on these movements to where these individuals can continue maintaining blood flow and oxygen delivery while diverting blood flow from lower to upper body. So these tend to be at the kind of things that we would give to delivery limited athletes. They sound pretty standard, but for these individuals, they tend to make like really fast improvements once you start shifting them away from like compelling in their limitation over and over to actually training something that's going to be specific to what their problem is and that's kind of like the core idea behind most of the book. It's like none of the protocols are that fancy. It's all things that someone's probably seen before. The idea is just that you have matched in the protocol to the individual instead of just taking something that looks cool that might not, you know, actually train these specific persons limitation. You provide some formal training and then you change it to something else that seems really almost like bog standard but it changed the physiological system in a completely different way which then has a great impact and yeah it definitely made me reflect when you said you know you're deliberately trying to train the mitochondria but then the mitochondria doesn't have what it needs to train if you know what I mean. So yeah it's great and I think that's why this information is so important because they are small tweaks which to the naked if you're not too familiar with exercise science may look the same but actually when you actually look at it in a more deeper level they are actually very different. Bringing it back to the archetypes because a lot of what we talked about is utilized near and see what's happening in the muscle. What happens if you don't have a near device? Are there physiological responses that the athlete can feel which may as a proxy inform they may be one of one of the three types of limiters? Yeah absolutely so first I'm going to back into my answer on this I'll say what you're not going to feel because that's almost as just as important as what you can feel. So one of the things that I'd say is someone's subjective effort of what's limiting them during like a maximal test of endurance is a really bad proxy for what their limitation is because their perception is almost always wrong and I've seen this play out dozens of times where all these sensors on athletes it's almost like a game when I was a training thing tank we had finished putting someone through an assessment I'd be like would you feel was limiting you and I would want to hear like them kind of walk through just to see like this anyone really like get a good sense of this and say there may be a few cases where someone actually identified it but it was because they they kind of knew the song and dance of like how we would play this game. There's actually a really good reason for this though. So do you use a strength training example imagine you're doing like a one right max back squat and you know you and evidently seen someone who they kind of get like dumped forward and I end up doing like a good morning with like 200 kilos one of the things that was always kind of mind blowing to me is when you see that happen and someone gets dumped over and they kind of like good morning up and people would always say particularly like the west side power lifting world there's like oh that's a sign of like a lower back like issue like that person needs to train their spinal rectors and get their lower back stronger so they don't get dumped over and I'm like what are you talking about that person just good mornings 200 kilos like their lower back is insanely strong and it's because your perception of like what the limitation is that person finishes a squat and they're like oh my god my back feels horrible like I do need a strength in my back it's like no the only reason you finished that was because your back is so strong you need to train everything else so that doesn't happen the same thing is true when someone's doing a test of max more endurance so oftentimes particularly with respiratory limited athletes you would ask them like what was limiting you they're like oh my arms and legs just felt like concrete at the end like complete lead I couldn't move them so like I need to improve my local muscular endurance or a delivery limited athlete would say oh I got so pumped during this workout like I just felt like I'd so much blood my arms and legs that's the problem it's almost never with actual issue is what you end up feeling when you're doing a test of max more endurance the thing that you think limits you is actually typically your strongest system the thing that's really your limiter kicked out like five ten minutes earlier and you've been relying on compensation patterns to keep you going so that's why subjective experience tends to not be great that said there are certain patterns that you could look for in an athlete's both performance data and in general experience that could help you and I'll even throw in some cheap technologies that you could use as well for utilization limit of athlete the telltale sign here is if you've ever worked with an individual you see this on their strength and speed work you're like okay what's your one rep back squat and they're like 100 kilos what's your three rep max back squat 101 kilos what's your 10 rep max back squat and they're like 105 kilos and you're like those are all the same number your 10 RM and your 1 RM like they're the same thing and you would see that in their speed curves as well you're like if you look at their 500 meter row their 1k their 2k their 5k you're like these are all effectively the same pace it's kind of that one year athlete where they have their speed and they could hold it forever and if you shorten the distance they don't get that much faster in terms of their average pace so that's kind of a signature there the caveat would be there also another form of utilization limitation that would be technically it's called an extraction limitation that isn't the same physiologic mechanism that's a little bit less common design there would be someone who hyperventilates for no reason when they're exercising so if you would have someone at a very low intensity and they just start hyperventilating they breathe off while they're carbon dioxide they're also going to impede their ability to utilize oxygen in the muscle that's because you're altering chemoglobin's binding curve for oxygen it looks like a utilization limitation it's actually just a breathing issue but that's kind of that phenotype that one gear individual has trouble gaining strength has trouble gaining muscle mass on the delivery limited athlete side one of the kind of telltales and you see this even more in crossfit sports that have some kind of like muscular endurance component is the person that always gets pumped out the other big telltale on crossfit is you have individuals where if they're doing like gymnastics movements and isolation for example you're like oh they could rip out like a set of like 20 unbroken ring muscle ups they could do 30 muscle ups and three and a half minutes could do 50 handstand pushups unbroken and then you put any of those movements in a metcon when they're having to like combine it with squats or running and all the sudden they can't do any of those movements anymore they're like how you could do sets of three muscle ups and then you fall off like the rings but meanwhile could do 20 unbroken otherwise that tends to be another signature of this delivery limited athlete and then kind of the opposite of utilization in terms of their speed curves these are people who they're drop off tends to be much larger than you'd suspect it to be so if you don't look at their 500 meter their 1k is disproportionately slow their 1k to 2k their 2k is disproportionately slow 2 to 5 you kind of see the same pattern playing out those are some of the indications there and then on the respiratory limited athlete one there's a few signs here summer visual summer physiological both things that you could look at one is respiratory limited athletes depending on whether sometimes it is structural so you could have an respiratory respiratory muscle weakness people with weak respiratory muscles tend to get stuck in hyperinflation patterns they're kind of have this stuck like chest up posture essentially they're really good at breathing in but they never fully exhale so they end up essentially with like their chest up typically they have a large slammed in their clavicle so essentially because they're not fully exhaling the superficial neck muscles pull upwards on the clavicles to create vertical space for the diaphragm and these people end up typically with like neck shoulder trap issues that's more of a structural limitation you see the same thing within respiratory muscle weaknesses oftentimes these are people that have very like chyphotic postures and that compares their breathing if we're to talk about the like real physiologic version of a respiratory limitation which is that pulmonary diffusion issue this is one where you see it a lot in the lead endurance athletes were after they finish like they pushed a failure their lips will turn a little bit blue oftentimes their fingers and their toes go numb and that's typically because they're not getting blood and oxygen to their periphery you'd also see if you had a pulse oximeter which you know anyone could buy their typically maybe $20 these are individuals who get really large drops in peripheral oxygenation after maximal effort activity so in a normal healthy person you typically don't really see any changed during exercise there'll probably be somewhere between 97 and 99% saturation on a pulse ox before exercise they should be thereafter if this is an individual that doesn't have any other pulmonary issues and they do like a maximal effort to okay and you're seeing them sitting like 88 percent that's a good sign that they have a respiratory limitation it's a really easy diagnostic so these are all things that you could you know use to try and identify a limitation without needing to go spend however much money on lab testing or having your own technologies sure and just to touch on the structural limitations how much do you would you say that influences the respiratory limitation just for my sense of they paint a really interesting picture around symptoms and body position but I would hate people to listen to this and think right they start really looking in for that in their athletes and start to miss judge anatomical variation between people, if you know what I mean, is it very, are these structural limitations very obvious to see, if you know what I mean? Yeah, so this is a good point because you do want to know what neutral looks like for someone before you say, "Oh, they have this posture of a respiratory limitate of the uric damp, might just be with their skeleton looks like." So typically you would want to know what is neutral for this individual look like before you make that diagnosis. There's also two considerations of someone is presenting with this type of respiratory limitation. It might not be their true physiologic issue. For example, if someone does have weak respiratory muscles, it's like, well, maybe even after you do fix the posture, they still have a respiratory limitation because their respiratory muscles are weak. It might also be masking another underlying limitation, though, so you might see kind of like gross changes in their limiter profile, particularly in a endurance training. But this is why really anytime I'm looking to identify a limiter, what I'm also asking is, what is your sport even? Because you might have one of these limiter profiles and how it manifests in your sport could vary depending on, you know, truly what your sport selects for. So I'm typically looking on these fingerprints that kind of transcend any one assessment. If we think someone is utilization limited, we're like, this should pop up in your endurance training and your interval training, your resistance training, like we should see this being a consistent phenotype, same thing with the delivery limitation. So, you know, you always want to have more than one data point to crop right this. I wouldn't just say like how we saw this one thing one time and like, that's definitely how we should prioritize everything you do for your out out. And that's an interesting actual segue, which I wanted to talk about next because I think people can get really caught up on one data point or one specific thing rather than trying to understand how many different things interact. Because I kind of wanted to finish on how we can use near data to make programming decisions when it comes to how long to recover, volume intensity. Because I, one of the bits from the book that I really, really enjoyed was the section around recovery volume intensity and how we can utilize that information to do it. And really, when it comes to these, there isn't like a specific data point that you need to look at. It's kind of rate of change, how that changes as the athletes exercising when they're not exercising that type of thing. So my question is how can we use it effectively? So if we want deceptoration to happen to what level of percentage and how do we use that as a training metric as we go through training, lots of it is quite a broad question really, because if it's to 40%, why 40%, who's making that decision, you know? So how can we utilize near data to make those training decisions and use it to progress the athlete forward? Yeah, absolutely. So I really like passive data collection. And then essentially using like retroactive analysis to try and inform training decisions. So I think one of the really hard things that anyone finds is particularly if you're onboarding a new technology and you don't have normalized data, you're like, what does the data mean? How do I take what I learned using it with this athlete and apply it to that one? So typically what I'll do with athletes is one, just have them start wearing it during their normal training. Presumably if we're prescribing something for an athlete, we have a reason why we want them to do it in the first place. And we want to know, well, what is the trend to look like if we're not trying to intervene? Now the way that I end up using this technology and practice would be a lot of it is doing one of two things. So I'm giving an athlete, let's say a certain interval training protocol, and I know what response I want them to have there. Well, now we have near data. So let's say just for something really easy, it might not even be something that would use, it's got four by four, like traditional like VO2 max protocol, four minutes at a really high intensity, four minutes rest, repeat that four times. Eric, okay, let's say we want to have an athlete do this like multiple weeks in a row and essentially make progress. We give them that protocol, they tell us how they did, we look at their power output, and now we need to know the next week. We want to manipulate that. Maybe we want to break even from that four by four structure, but where do we increase the duration a little bit? Do we shorten the rest? Do we increase the intensity? What do we do there? One of the ways that I would use near data is let's say we have that data and I see basically across those four sets, the athlete kind of bottomed out their oxygen level on all of those intervals. Look, okay, we've exhausted this progressions wrongly. So we're not just going to increase their intensity, it's not going to do anything for the athlete. Based on that data, do we think we could extend the interval out a little bit? Do we think we could, or you know, is it truly exhausted? If it is exhausted, it would be a case where I'd say, okay, so now we know that the athlete bottomed out their oxygen supply, they're not going anywhere with that. Maybe let's take a week or two step back and say, could we try and improve their delivery a little bit? And then come back to that protocol. Do it the exact same intensity and see, are they work? Did they finish it with the higher oxygen saturation? They're muscled in last time? Okay, sweet. Now we extend their runway and now we could do like a very straightforward progression. We could just keep increasing intensity. On the flip side, let's say the athlete does the protocol, and there I got it was pretty tough and I'm like, oh, dude, you have like 40% oxygen saturation, each of those sets. Like, let's increase the intensity. We could run it. So a lot of what I do in practice is essentially saying, like, give the protocol see their response to the athlete ever on way to improve if they do. I give people the same workout over and over again. And like it might seem like lazy coaching, but I'm like, you didn't like squeeze all the juice from this orange. If you want to use that analogy, like you could just keep squeezing, you're going to get more out of this. And we're just going to keep doing it over and over and over again until you don't continue getting something. And when you don't, we're going to see why you're not getting better. Then we're going to shift the protocol to bias. Whatever is now the rate limiting factor. And then we're going to do that over and over and over again. Now, consider that they're doing a lot of different training across the week. They're not just doing this one interval training. They also have strength training, other endurance training pieces they're doing. So a lot of times things are getting moved around the week and kind of recombined in different orders in a way that makes a logical sense. Because if we see they bottom out their oxygen on those like four by four intervals and we can just switch it to a new protocol to extend the runway. Well, if they were doing that session say Tuesday morning and now we switch it to something else and like that new session might not make sense to do in that place. So we need to like push things around the week to accommodate the new change and maybe another thing change. So a lot of the week to week training that I give athletes is just like reordering and recombining things pulling pieces out like subbing something else in and taking those other things off the back burner and putting them back in. So it's kind of like a bunch of these moving parts that it seems complicated if you don't know the logic behind it. But when you see the data that's being used to inform those decisions, it actually makes coaching relatively easy because you don't need to be as imaginative with what you're doing. You just have data that says they stopped progressing on this thing. Here's why give them something that solves that issue and kind of makes it a little bit more straightforward. That makes complete sense to me. One because a lot of people criticize testing sometimes because one they seem to expect that people need to make decisions on every single data collection and that clearly isn't the case. Like retrospectively, a lot of data collected is going to tell you a huge picture about that athlete that will really help with decisions going forward. And one of the other criticisms is that testing is a group of test battery that you have to act maximally in each one, which is obviously fatigue and then can take away from the actual sport. So it's something like this where you're getting the same thing over and over again, but you can clearly see using something like Niers how the athlete is improving and you can make very clear decision from that. To me, it makes complete sense and isn't lazy coaching because you're actively saying how that person is adapting/improving. And it's definitely something to think about when you see so many programs out there where it's like eight to 12 weeks and there's a structured improvement with each week. At the end, you're going to improve. Well, probably because you've just repeated the tests, but physiologically, have you actually improved? So I think this is really important for all coaches and athletes. And hopefully more and more people will read your book and this message will come across really clear. Yeah, that would be great. Yeah, and this even applies. It's just training in general. So a lot of times it's like working with new athletes. They expect you to overhaul their entire program like a higher than new coach. And I'll say like, well, what have you been doing? What are like the minimal number of tweaks that we could make just kind of like moving things around a little bit like tweaking how you're doing the intercept pace and see if you get progress and then just build off of that and continue. So yeah, to your point, it seems lazy, but when you understand the logic, it's like training really doesn't need to be complicated. A lot of the like flashy protocols and you see or essentially marketing tactics, but you know, if you just make a very minor tweaks, you could continue kind of milking out progress from really long periods of time. Whatever, that was absolutely brilliant. It's been really, really cool to catch up and thank you for the opportunity to read your updated version of paradigm shift. I really appreciate it and learnt a lot. What's next for Evan? If someone wants to work with you, what do they need to do? Yes, so these days I'm really only working with organizations and teams right now. So primarily, uh, scientific advice and then consulting work for, uh, sports teams, uh, startup companies. If anyone is interested in that, um, my personal website is just my name, EvanBicon.com. Uh, you could find everything I do there, whether that's writing, uh, links to the book, uh, consulting context, so everything's kind of stored in one easy place. Yeah, definitely, and I highly recommend anyone listening that wants to learn a bit more. Check out Evan's sub-stack. You've got two sub-stacks with both of which I enjoy, but obviously are kind of different. One's more on the oncology side. The other side is more of the human forms, but even if you're not familiar with oncology and that type of thing, you do tend to learn quite a lot on reading it, so I definitely recommend it. But yeah, thank you. Evan, that was awesome. Thank you so much. Yeah, thank you for having me. Appreciate it. Before we wrap up, I want to give a shout out and my thanks to my production partner, Cult Media. If you are thinking of launching a podcast or want to grow your audience, head to www.cult.media that's Cult with a K to get started today.